Computer networks provide an infrastructure that enables communication and exchange of information among computer systems that are coupled to the network. In many cases the individual networked systems may reserve resources to accommodate communications with the other networked systems to which they are coupled. In the event of a power failure such resources may be wasted as the resources may continue to be reserved for systems that have experienced a power failure and are no longer capable of communicating.
Dying gasp features allow a message that details the imminent loss of power to a networked component to be sent over a network after the detection of the imminent loss of power. In conventional systems dying gasp systems require up to 50 ms in order to complete the process of transmitting a dying gasp message upon the detection of an imminent power failure.
Customer premise equipment (CPE) network devices that support various Digital Subscriber Line technologies (xDSL) and Integrated Services Digital Network (ISDN) are generally required to support a dying gasp system. A dying gasp system typically consists of a voltage supervisor (either external or built in to the chipset) that manages the power supply voltage and notifies the xDSL or ISDN chipset in the event that it detects a power loss. The xDSL or ISDN may then relay a message to a central office (CO) that indicates an imminent power failure.
Because of the increasing power demands of high-bandwidth xDSL chipsets such as ADSL2/+ and G.SHDSL chipsets, the amount of energy storage required to sustain the 40-50 ms of uptime may be expensive. The main form of energy storage is provided by capacitors and the amount of capacitance required is determined by the power consumption of the Wide Area Network (WAN) chipset and the power supply efficiency of the device.
Low cost power supply implementations generally use linear drop-out regulators. However, many systems that employ this approach have been found to suffer from low efficiency. Other implementations such as switchers are much more efficient but are also more expensive. These conflicting design constraints make the implementing of a cost effective dying gasp system challenging. It should be appreciated that although very large capacitors may be used to meet power demands, such approaches may be space and cost prohibitive.